Self-loading firearms are presently in use throughout the world and have become the dominate firearm type in modern manufacture. Chief among the advantages which have lead to the domination of self-loading firearms is the utility of various rapid fire capabilities which self-loading firearms known to the art are capable of.
Self-loading firearms are those wherein the next live ammunition cartridge loads after a live ammunition cartridge has been fired. Once the firearm is made ready to fire, the user need only interact with the fire control group of the firearm in order to fire a live ammunition cartridge and load the next available live ammunition cartridge from a magazine, belt or other ammunition feeding device, such that the firearm is made ready to fire again without additional user interaction.
The fire control groups for self-loading firearms known to the art frequently share many characteristics of how they are operated by the user. For most such fire control groups a semi-automatic firing mode is provided. Said semi-automatic firing mode is such that the user fires the firearm by using a finger to apply force to the trigger of the fire control group until the trigger is moved from its reset position to its firing position, at which point a live ammunition cartridge is fired. Once the firearm has been fired in said manner, in order for the user to fire an additional live ammunition cartridge, the user reduces the force being applied to the trigger with his or her finger, thus allowing the trigger to return to its reset position. After this, the user again applies increasing force with his or her finger to the trigger until the trigger is again moved to its firing position, causing the firearm to fire an additional live ammunition cartridge. This process may be further repeated to continue firing additional live ammunition cartridges until live ammunition cartridges are no longer available to the firearm.
This semi-automatic firing mode as found in semi-automatic fire control groups known to the art is disadvantageous for multiple reasons, including but not limited to:
a) Firing multiple live ammunition cartridges requires the user to both increase and decrease the force applied to the trigger with his or her finger. This requirement is time consuming and significantly limits the potential rate of fire.
b) The repeated alternation between contraction and relaxation of the muscles in the users finger is physically taxing, and thus, may induce cramps and even exhaust the ability of the users finger to pull the trigger at the desired rate of fire.
c) The time consumed by the requirement for the user to reduce force applied to the trigger in order for the next live ammunition cartridge to be fired may be in excess of the time required for the user to aim the firearm, resulting in an unnecessary delay between the firings of live ammunition cartridges.d) A trigger spring with significant strength is required to bias the trigger towards its reset position. This results in a heavier trigger pull weight.
These and other disadvantages in the state of the art have led to the incorporation into many fire control group designs both a semi-automatic mode as previously described, and an additional fully-automatic mode of fire. Said fully-automatic mode of fire is such that the firearm will continue firing live ammunition cartridges as long as the trigger is held in the firing position and the firearm has available live ammunition cartridges. This fire control group with both semi-automatic and fully-automatic firing modes alleviates some of the above disadvantages found in firearms which are only capable of semi-automatic fire.
However, fire control groups with both semi-automatic and fully-automatic firing modes, as known to the art, suffer from a number of disadvantages, including but not limited to:
a) Many firearms known to the art which incorporate fire control groups with both a semi-automatic and a fully-automatic firing mode also incorporate a selector switch which the user must manipulate in order to change between the low rate of fire semi-automatic firing mode and the high rate of fire fully-automatic firing mode. Manipulating such a selector switch is time consuming and burdensome for the user of the firearm.b) Firearms known to the art which incorporate fire control groups with both a semi-automatic and a fully-automatic firing mode require additional parts and complexity when compared to firearms which only incorporate a semi-automatic firing mode. This is a burden on manufacturing and can be a source of reliability problems and increased cost.c) The fully-automatic firing mode of many firearms known to the art typically does not provide the capability for the user to adjust the rate of fire of the firearm during the process of firing the firearm.d) Firearms known to the art which incorporate a fully-automatic firing mode often have an excessively high rate of fire, this excessively high rate of fire produces a recoil force beyond that which is easily controlled by the user. This excessively high rate of fire may result in the firearm dangerously and uncontrollably drifting off of the desired target. Such an excessively high rate of fire may also consume ammunition at an undesirably high rate.e) Under stress the firearm user may unintentionally clinch his or her firing hand, depressing the trigger with his or her finger. This can result in the firearm entering a very dangerous runaway firing condition at a high rate of fire until the user regains control of the firearm or the firearm runs out of ammunition.
The above disadvantages present in fire control groups known to the art which incorporate a fully-automatic firing mode have led to many firearm designs which incorporate a feature called arate-reducer. This feature typically comprises a mechanical device installed within the firearm which slows the firing rate of the firearm during firing in fully-automatic mode in order to alleviate some of the above disadvantages found in firearms with fully-automatic firing modes.
However, firearms operating in fully-automatic mode while equipped with a rate-reducer still suffer from disadvantages, including but not limited to:
a) Firearms known to the art which incorporate a rate-reducer for reducing the fully-automatic firing rate require additional parts and complexity. This is a burden on manufacturing and can be a cause of reliability problems and increased cost.
An example of an attempt to resolve the aforementioned disadvantages of semi-automatic fire control groups can be found in U.S. Pat. No. 8,371,208 to Cottle, wherein a sliding articulation is added to the firearm stock such that when the firearm fires live ammunition the resultant recoil force moves the receiver of the firearm away from the users finger. This movement of the firearm away from the users finger allows the trigger to return to its reset position. Said movement of the trigger to the reset position as a result of recoil force allows for a faster rate of fire. However, this concept adds considerable complexity to the firearm, does not lend itself to practical use and has proven to be unreliable for many users. Thus, this concept does not resolve the existing disadvantages in the state of the art.
Another example of an attempt to resolve the disadvantages of semi-automatic fire control groups is U.S. Pat. No. 8,667,881 to Hawbaker, wherein a fire control group is described which fires live ammunition both when the trigger is moved to the firing position, and also when the trigger is returned to the reset position. This concept essentially doubles the potential rate of fire compared to a typical semi-automatic fire control group. However this concept does not approach the high rate of fire of many fully-automatic fire control groups. Additionally, it adds considerable complexity to the fire control group when compared to typical semi-automatic fire control groups as known to the art. As such, this concept does not resolve the existing disadvantages in the state of the art.
A further example of an attempt to resolve the disadvantages of semi-automatic fire control groups is U.S. Pat. No. 5,074,190 to Troncoso, wherein an apparatus which provides spring bias to the trigger in the direction of the reset position is described. This concept, however, applies said spring bias to the trigger throughout the process of firing the firearm. As a result the users finger must apply additional force to the trigger in order to move the trigger from the reset position to the firing position. This additional force which the user must apply is equal to the added spring bias towards the reset position applied to the trigger. Thus, once the trigger is moved to the firing position, the user is still required to reduce the force applied to the trigger with his or her finger in order to fire the firearm again. As a result this concept does not resolve the disadvantages of semi-automatic fire control groups known to the art.
With these facts identified it is clear that fire control groups known to the art have many disadvantages. In order that self-loading firearms be equipped with a fire control group which eliminates these disadvantages, a new type of fire control group is needed. Despite this need, the state of the art does not allow for a fire control group which resolves these disadvantages, and therefore is greatly lacking.